JP2014526780A - Digitally controlled electronic ballast with discharge fringe prevention control and operation method thereof - Google Patents

Abstract

  An apparatus for powering one or more gas lamps, determining a turn-on time (Ton) for a period having a plurality of segments and lasting a predetermined time interval according to a 50 percent duty cycle. And a half bridge circuit having a discharge fringe control circuit that modulates Ton1 and Ton2, which are ON times of the first and second power switches of the half bridge circuit, according to the discharge fringe control method for each of the plurality of segments. ,apparatus.

Description

  The present application relates to digitally controlled electronic ballasts for driving fluorescent lamps. More specifically, the present invention relates to an electronically controlled electronic ballast with a striation function that reduces or eliminates discharge fringes when driving a fluorescent lamp, and an operation method thereof.

  Under certain operating conditions, fluorescent lamps (hereinafter referred to as lamps) may cause discharge fringes. Discharge fringes are visible stripes in alternating light and dark areas that travel over the length or length of a portion of the lamp and appear in new energy-saving lamps as well as standard lamps. Appears in the lamp as a visible stripe. The discharge fringes can be stationary or move across the lamp at different speeds and can therefore appear as standing waves to the viewer.

  The possibility that the gas lamp forms discharge stripes that emit light can be predicted based on the physical structure of the lamp. For example, many new energy-saving lamps contain a high density fill gas, such as krypton. The dense filling gas may increase the possibility of forming discharge fringes, especially when operating the lamp at low temperatures. Also, operating the ballast in dimming mode to drive the fluorescent lamp at the low current level used to dim the lamp has the potential to form discharge fringes under certain operating conditions. May increase.

  Therefore, it is desirable to improve the conventional ballast drive circuit for controlling the ballast output to a load such as a fluorescent lamp in order to control, reduce or prevent discharge fringes.

  The system controls, reduces, and / or discharges fringes in various operating conditions (eg, low temperature, normal temperature, high temperature, various temperature ranges, abnormal conditions, etc.) and various operating settings (eg, dimming, high brightness, startup, etc.) Or, a system, method, circuit, apparatus, and computer program part for controlling a ballast that drives a fluorescent lamp to prevent (hereinafter, unless otherwise specified, these may be referred to as a system, respectively). Is disclosed.

According to one aspect of the system, for driving a switching half-bridge circuit for supplying power to a load that includes one or more gas lamps (eg, linear fluorescent lamps). An apparatus is disclosed. The device includes a half-bridge circuit with a corresponding Ton at a duty cycle of approximately 50% during the first operating mode such that Ton1 and Ton2 of each of the first and second switches are approximately equal to Ton during the period. A half-bridge driver that supplies a control signal for driving the first and second power switches of the power supply; and whether or not to operate in the discharge fringe control mode (SCM) and if it is determined to operate in the SCM , A discharge fringe control circuit that sets Ton1 and Ton2 according to the discharge fringe control setting. Further, when it is determined that the discharge fringe control circuit operates in SCM, Ton1 and Ton2 are set so as to be different from each other in a predetermined segment, and different from Ton for a plurality of segments in the cycle. In this way, Ton1 and Ton2 may be set. Furthermore, when operating in SCM, the discharge fringe control circuit may set Ton1 and Ton2 according to a predetermined discharge fringe control pattern. Further, the discharge fringe control circuit may set Ton1 and Ton2 according to the following formula for a plurality of segments (i) in the cycle:
Ton1 (i) = Ton + kx (i), and
Ton2 (i) = Ton−kx (i),
Where Ton may be set to regulate the current delivered to the load according to a 50 percent duty cycle, k is a constant, and x (i) depends on each segment (i) Change.

  The discharge fringe control circuit may determine whether or not the last segment (i) of the plurality of segments is completed, and the plurality of segments starting from the first segment of the plurality of segments. It is envisioned that one or more of these may be repeated until it is determined that the cycle is complete.

  Further, the discharge fringe control circuit may determine whether or not the discharge fringes are present in the output of the one or more gas lamps, and determine that the discharge fringes are present in the output of the one or more gas lamps. In this case, it is assumed that the SCM may be operated. Further, the discharge fringe control circuit may determine whether to operate in SCM based on one or more of dimming settings and temperatures of one or more lamps.

  According to an additional aspect of the system, an apparatus is disclosed for supplying power to one or more gas lamps, the apparatus having a plurality of segments according to a 50 percent duty cycle and a predetermined time interval. Determining the on-time (Ton) for a lasting period and / or the on-time of each of the first and second power switches of the half-bridge circuit according to the discharge fringe control method for each of the plurality of segments; A half bridge circuit having a modulation control circuit for modulating Ton2 may be included. The apparatus may further generate first and second drive signals for driving the first and second power switches, respectively, according to Ton1 and Ton2.

According to another further aspect of the system, a method of controlling a switching half bridge circuit for supplying power to a load, which may include one or more operations performed by a processor, is disclosed. Is done. During the first operation mode in which Ton1 and Ton2 of each of the first and second switches are substantially equal to Ton in the period, the operation of the half-bridge circuit is performed with a corresponding Ton at a duty cycle of approximately 50%. An operation of supplying a control signal for driving the first and second power switches; an operation of determining whether or not to operate in a discharge fringe control mode (SCM); and / or a case of determining to operate in the discharge fringe control mode The operation of setting Ton1 and Ton2 according to the SCM method may be included. When it is determined that the method operates in SCM, Ton1 and Ton2 are set to be different from each other in a predetermined segment, and Ton1 and Ton2 are set to be different from Ton for a plurality of segments in a cycle. It may further include an operation of setting. Further, the method may include an operation of setting Ton1 and Ton2 according to a predetermined discharge fringe control pattern when operating in SCM. The method may also include an operation of setting Ton1 and Ton2 according to the following formula for a plurality of segments (i) in the cycle:
Ton1 (i) = Ton + kx (i), and
Ton2 (i) = Ton-kx (i).
Here, Ton is set to regulate the current supplied to the load according to a 50% duty cycle, k is a constant, and x (i) varies with each segment (i).

The method also includes an act of determining whether the last segment (i) of the plurality of segments is complete; and one of the plurality of segments starting from the first segment of the plurality of segments. It is envisioned that an operation may be included that repeats one or more until it is determined that the cycle is complete.

  Further, the method determines whether there is a discharge fringe in the output of one or more gas lamps, and determines that there is a discharge fringe in the output of one or more gas lamps. It is envisioned that one or more operations may be included that operate at The method may also include an operation of determining whether to operate with the SCM based on one or more of dimming settings and / or temperatures of one or more lamps.

  According to a further aspect of the system, a method for controlling a switching half bridge circuit for supplying power to a load is disclosed. The method may include one or more operations performed by the processor. The operation includes an operation of determining an on time (Ton) for a period having a plurality of segments and lasting for a predetermined time interval according to a 50% duty cycle; and / or a discharge fringe control method for each of the plurality of segments , Including the operation of modulating Ton1 and Ton2, which are the ON times of the first and second power switches of the half-bridge circuit, respectively. The method may further include generating first and second control signals for driving the first and second power switches, respectively, according to Ton1 and Ton2.

According to a further additional aspect of the system, a computer program for controlling a switching half bridge circuit for supplying power to a load stored in a computer readable storage medium is disclosed. The computer program has a duty cycle of approximately 50% with a corresponding Ton during the first operating mode such that Ton1 and Ton2 of each of the first and second switches are approximately equal to Ton in the period. When generating a control signal for driving the first and second power switches of the half-bridge circuit; determining whether to operate in the discharge fringe control mode (SCM); and determining to operate in the discharge fringe control mode In addition, a computer program part for setting Ton1 and Ton2 according to the SCM method may be included. When it is determined that the computer program part operates in SCM, Ton1 and Ton2 are set to be different from each other in a predetermined segment, and Ton1 is set to be different from Ton for a plurality of segments in a cycle. And Ton2 may be set. Further, when the program portion operates in SCM, Ton1 and Ton2 may be set according to a predetermined discharge fringe control pattern. The program part may further set Ton1 and Ton2 according to the following formula for a plurality of segments (i) in the cycle:
Ton1 (i) = Ton + kx (i), and
Ton2 (i) = Ton-kx (i).
Where Ton is set to regulate the current supplied to the load according to a 50% duty cycle, k is a constant, and x (i) varies with each segment (i).

  According to a further additional aspect of the system, a computer program stored on a computer-readable non-transitory storage medium is disclosed. The computer program determines a turn-on time (Ton) for a period having a plurality of segments and lasting a predetermined time interval according to a 50 percent duty cycle; and according to a discharge fringe control method for each of the plurality of segments. Modulating Ton1 and Ton2, which are the on times of each of the first and second power switches of the bridge circuit; and / or first and second for driving each of the first and second power switches according to Ton1 and Ton2. A computer program part for generating the second control signal may be included.

The invention will be described in more detail and by way of example with reference to the accompanying drawings.
1 is a schematic diagram of a ballast circuit 100 that supplies power to a load that includes a lamp 106 according to embodiments of the present system. FIG. It is a flowchart explaining the process according to the several Example of this system. FIG. 10 is a screenshot of a graph 300 illustrating pulse width modulation (PWM) output from a controller to a half-bridge driver for generating the current envelope shown in FIG. 9 according to embodiments of the present system. It is a graph which shows the envelope of the lamp current without discharge fringe prevention modulation. FIG. 4 is a screen shot of a graph showing an envelope of lamp current with discharge fringe control modulation (SCM), according to embodiments of the system. FIG. 4 is a screen shot of a graph showing an envelope of lamp current with discharge fringe control modulation (SCM), according to embodiments of the system. FIG. 4 is a screen shot of a graph showing an envelope of lamp current with discharge fringe control modulation (SCM), according to embodiments of the system. FIG. 6 is a screenshot of a diagram illustrating an envelope of lamp current with discharge fringe control modulation (SCM), according to embodiments of the present system. FIG. 4 is a screen shot of a graph showing an envelope of lamp current with discharge fringe control modulation (SCM), according to embodiments of the system. FIG. 2 illustrates a portion of a system according to embodiments of the present system.

  In the following, exemplary embodiments will be described. These embodiments show additional features and advantages in addition to the features and advantages described above in connection with the following drawings. In the following description, for purposes of explanation and not limitation, example details will be set forth as architecture, interface, technology, component attributes, etc. However, it will be apparent to one skilled in the art that other embodiments that differ from these details are also within the scope of the appended claims. In addition, for purposes of clarity, detailed descriptions of well-known devices, circuits, tools, techniques, and methods are omitted so as not to obscure the description of the present system. It should be expressly understood that the drawings are included for illustrative purposes and do not represent the scope of the present system. In the accompanying drawings, like reference numbers in different drawings may indicate similar components.

  FIG. 1 is a schematic diagram of a ballast circuit 100 that supplies power to a load 116 that includes a lamp 106, according to embodiments of the present system. The ballast circuit 100 may use digital control for the output stage and includes one or more controllers 102 (eg, microprocessors) that control the operation of the output stage, such as the half-bridge circuit 104 that drives the load 116. May be included.

  The load 116 may include any suitable load circuit, such as one or more lamps 106. The one or more lamps 106 may include one or more gas lamps such as a plurality of fluorescent lamps (eg, a linear fluorescent lamp (LFL), a small fluorescent lamp (CFL), etc.).

  The half-bridge circuit 104 may include a high gate Q1 and a low gate Q2, and the load 116 and, for example, the load 116 to supply power to one or more lamps 106. May be driven. The high gate Q1 and the low gate Q2 may each include any appropriate power switch such as a transistor switch (eg, a power MOS such as MOSFETS). During operation, the load (lamp) becomes like a resistor and has a negative impedance characteristic. As the lamp current is reduced, the lamp voltage increases. The lamp is lit by being driven near the no-load resonance frequency of Lr and Cr (C1 is usually selected to be a very large value compared to Cr, so the influence on the resonance frequency is minimized). Is done. In this way, a high voltage is generated to light the lamp. After lighting, the load (lamp) is driven at a predetermined frequency, thereby limiting the current through it.

A current shunt resistor circuit 114 is installed along a load return path that can be associated with Q2 to at least partially limit the half-bridge output current (I _LOAD ) of the half-bridge circuit 104. May be. The current shunt resistor circuit 114 may include capacitors CSC1 and CSC2 and resistors SCR1 to SCR3, and information about the current (eg, I _LOAD ) flowing through the load 116, eg, one or more lamps 106 A feedback (FDBK) signal such as IHB_av may be generated that can provide information about the lamp current (I _LC ) flowing therethrough.

The current shunt resistor circuit 114 can provide a voltage signal (eg, FDBK signal IHB_av) proportional to the half-bridge output current (I _LOAD ). Since a constant voltage from the PFC 112 is supplied to the half bridge 104, this signal (for example, the FDBK signal IHB_av) is also proportional to the half bridge power. Since the loss for half bridge 104 is known, the lamp power (of one or more lamps 106) can be calculated by subtracting the loss from the half bridge power. However, it is envisioned that other methods can be used to obtain lamp power. The current shunt resistor circuit 114 is just one exemplary method. Other methods may include shunt resistors in series with loads, current transformers, and the like. In particular, it may be necessary to limit lamp power when dimming to maintain a constant light level from one or more lamps 106 at low dimming levels. However, it should be understood that in all embodiments, such as those in which the lamp cannot be dimmed, a current feedback circuit may not be necessary. However, in the case of using a dimmable ballast, a current feedback circuit is used to control the half bridge 104 when dimming to maintain a constant light level from one or more lamps 106. May be preferred. Also, embodiments of the system may be compatible with non-dimming ballasts with or without any feedback, such as current feedback to monitor lamp current. However, as described herein, in some embodiments of the system, feedback such as current feedback is used to limit the power / current (of the lamp) by changing the ballast frequency. May be.

  The controller 102 may control the overall operation of the ballast circuit 100 or may operate under the control of one or more processors (eg, a microprocessor, logic device, analog or digital logic circuit, etc.). And may include a digital control regulator (DCR) 108 operable under the control of the one or more processors. The controller (eg, DCR) may include an analog or digital circuit to generate the first and second drive signals. The control unit 102 may control an output stage such as the half-bridge circuit 104 (a controller such as a DCR or PFC may include analog and / or digital circuits for generating the first and second drive signals, for example. A power factor correction (PFC) preconditioner 112 capable of supplying a regulated direct current (DC) voltage (eg, PFC + and PFC−) to the half-bridge circuit 104 at a desired voltage. May be included. Further, the control unit 102 may receive control signals from the user or the system, such as on / off settings and dimming settings. Control signals (eg, on / off, dimming level, etc.) are supplied by control circuitry (eg, dimming switches, on / off wall switches, etc.), automated controllers (eg, digital addressable lighting interface (DALI)). ) Controller) or the like. The control signal may be a wired and / or wireless network according to an embodiment of the system, such as, for example, an analog network, a dedicated network, a local or wide area network (LAN, WAN), a DALI network, and / or other wired / wireless connection. May be received.

  The DCR 108 can change the switch-on time that the half bridge 114 provides to the load 116 by controlling the operating frequency and / or power output supplied to the half bridge 104, and thus the half bridge 104 causes the load 116 to change. The power output supplied to can be controlled. Accordingly, the DCR 108 can drive the high gate Q1 and the low gate Q2 of the half bridge 104, respectively, to control the power output of the half bridge 104, and thus can control one or more lamps 106. . In order to drive the first and second gates (Q1 and Q2, respectively), the process may generate a first drive signal (eg, Gate_Drive_1) for driving the first gate (eg, Q1). In addition, a second driving signal (for example, Gate_Drive_2) for driving the second gate (for example, Q2) may be generated. The first driving signal (Gate_Drive_1) may be transmitted from the first gate output of the DCR 108 to the gate of the first gate (Q1) through the resistor R1. Similarly, the second drive signal (Gate_Drive_2) may be transmitted from the second gate output of the DCR 108 to the gate of the second gate (Q2) through the resistor R2. According to an embodiment of the system, the first drive signal has Ton1 corresponding to the on-time and the second drive signal has Ton2 corresponding to the on-time. In a normal operation mode (for example, a mode other than SCM), Ton1 and Ton2 are set substantially equal to Ton of the corresponding period.

Therefore, the half bridge 104 current output (I _LOAD ) is maintained at 50 percent, or (substantially) the frequency control “HO” input to Q 1 and Q 2, respectively, with the frequency for the duty cycle maintained at 50 percent. And “LO”. Also, a dead time allowance may be provided to prevent mutual induction via the gates Q1 and Q2.

To determine Ton, the DCR 108 may process the feedback information periodically or aperiodically, as supplied by the FDBK signal IHB_av, and controls the half-bridge current I _LOAD in the corresponding period. Thus, Ton for half bridge circuit 104 may be adjusted according to a 50% duty cycle. The corresponding period may have a duration of, for example, 850 μS (which may be based, for example, on the speed of the digital control loop of the control unit 102 of the system 100). However, it is envisioned that this period may have other durations. The value of Ton is unchanged in the corresponding period. However, at the end of the corresponding period (eg, the current cycle), the half-bridge current I _LOAD , and thus one or more, while maintaining a 50% (or substantially 50%) duty cycle for the next period Based on the current period measurement to modify the power of the lamp 106 and / or maintain control over it, the DCR 108 may update the value of Ton for the next period. Further, with respect to the half-bridge current I _LOAD , this current may be sent to the load 116 through a capacitor C1 and an inductor L1 (indication L _R ), for example.

The DCR 108 may include a discharge fringe controller (SC) 110 that controls discharge fringes at the output of one or more lamps 106. This can prevent, minimize, and / or eliminate the formation of discharge fringes output by one or more lamps 106. When activated (eg, in the SCM, or at other / all times if necessary), the SC 110 is configured to control the output of the half-bridge (eg, half-bridge current I _LOAD ). The DCR 108 may be controlled to modulate (eg, change) the first and second drive signals (eg, Gate_Drive_1 and Gate_Drive_2, respectively) according to the SCM technique. Thereby, discharge fringes at the output of one or more lamps 106 can be prevented, reduced and / or eliminated. Accordingly, the SC 110 can modulate Ton1 and Ton2 by setting or changing their values according to the SCM technique (eg, calculation, pattern, etc.). This ensures that the first and second drive signals Gate_Drive_1 and Gate_Drive_2 are each asymmetrically modulated during at least a portion of the corresponding period, respectively (for this, SC110 if necessary). The first and second drive signals can each be modulated. Therefore, unlike the above-described normal operation mode in which Ton1 and Ton2 are set to be substantially equal to Ton, during SCM, Ton1 and Ton2 are set according to the segments in the plurality of segments in the corresponding period. As such, Ton1 and Ton2 may be modulated (eg, according to a default value of the selected SCM technique). Also, with respect to a plurality of segments, each i-th segment (eg, segment (i)) in the plurality of segments may have a duration (also known as a segment time; for example, 50 μsec in this example). Accordingly, there may be I segments for each corresponding period. Here, the total number of segments (I) = (cycle time) / (segment time). Thus, in this example, there may be 850/50 = 17 segments. However, other numbers of segments are also envisioned. Between each of these I segments, SC 110 may modulate Ton1 and Ton2 according to the corresponding formula of segment (i), and for all segments of the corresponding period, as described below, Ton1 And Ton2 may be modulated.

  FIG. 2 shows a flow diagram illustrating a process 200 according to an embodiment of the present system. Process 200 may be performed by one or more computers communicating over a network. Process 200 may include one or more of the following operations. Also, if necessary, these one or more operations may be combined and / or separated into a plurality of partial operations. During operation, process 200 may begin during operation 201 and then proceed to operation 203.

  During operation 203, the process may drive the half-bridge circuit according to the current value of Ton for a period (eg, 850 μs in the current example). The value of Ton may correspond to, for example, a 50% duty cycle and may be generated according to a feedback signal (eg, IHB_av, etc.). Thereby, the current output of the half bridge to the load can be controlled, and the lamp output can be controlled. Assuming the process is in a mode other than SCM, the process may set Ton1 and Ton2 to be the same as Ton, and based on Ton1 and Ton2, the first and second signals are respectively , May be generated. Thereafter, the process may drive the first and second gates (Q1 and Q2, respectively) with the first and second drive signals for that period. After completing act 203, processing may continue to act 205.

During operation 205, the process may obtain one or more feedback signals during that period. The one or more feedback signals indicate a current supplied to the load, such as a feedback signal IHB_av. After completion of act 205, processing may continue to act 207. During operation 207, the process may determine the value of Ton for the next cycle. Thus, the process may analyze the feedback signal IHB_av and determine a corresponding Ton value for controlling the half-bridge current (eg, I _LOAD ) according to a 50% duty cycle. After completing act 207, processing may continue to act 209.

  During operation 209, the process may determine whether to enable SCM. Accordingly, if it is determined that SCM is to be enabled, processing may continue to operation 211. However, if it is determined not to enable SCM, processing may continue to operation 223. For example, if it is determined that discharge fringes appear in the lamp output (such as image analysis of the light output of the lamp), a specific dimming setting or range, temperature or temperature range (eg, low temperature or specific temperature) When a specific operation setting is detected, such as when operating above a threshold or below a specific temperature threshold, etc., and / or when a specific operation setting can be activated manually or continuously In (eg, always on), the process may determine to enable the SCM. For example, the process may use a look-up table to determine various operating conditions and / or modes (eg, start, low temperature, dimming, normal, steady state, failure, etc.) for which the SCM can be valid. Each lookup table may further be associated with a particular lamp and / or ballast set. Thus, the process may determine a set of lamps and / or ballasts and may obtain a corresponding look-up table, for example, from system memory. Since the discharge fringes may not occur in the entire dimming range of the ballast, the processing is a specific operating range or level of the ballast that does not require discharge fringe control (eg, dimming range or level). It may be determined that the SCM is invalidated. Thus, the generation of discharge fringes may be avoided in a plurality of setting ranges (eg, dimming range or level). Also, if discharge fringes are detected in the lamp output and / or under certain settings, the process may decide not to enable SCM. In addition, sensor feedback, such as lamp temperature, may be used by the process to determine when to activate SCM schemes and / or when to disable them. For example, the system may determine that discharge fringes may appear based on the particular dimming and lamp temperature, and thus the system may enable the discharge fringe control circuit. However, it is envisioned that in yet another embodiment of the system, SCM may be enabled at all times. Accordingly, processing may proceed from operation 207 to 213 if necessary.

  In operation 211, the process may select an SCM scheme. SCM schemes may include patterns, mathematical equations, etc., and are detected using any suitable method, such as by sensor analysis and / or feedback information related to ballast and / or lamp operation, etc. May be selected according to operation conditions (for example, temperature or temperature range, output current, etc.), operation settings (for example, dimming mode, energy saving mode, for example, frequency such as 200 Hz, modulation, etc.) For example, if it is detected that the ballast is operating in a dimming mode, the first SCM scheme may be selected, while if it is detected that the lamp is cold, a different SCM scheme is selected. May be selected. Therefore, the process may acquire the SCM method from, for example, a reference table acquired from the memory of the system in order to determine the corresponding SCM method to be used. It is also assumed that the process may select a default SCM method.

The process may also select an SCM scheme based on the desired output for a given lamp current envelope. For example, Tables 1 to 5 below show different SCM schemes. The different SCM schemes are shown in FIGS. 5-9, respectively, in the lamp of FIG. 4 (which is a graph 400 showing a lamp current envelope 402 with anti-current fringe modulation disabled) (eg, Corresponding to exemplary lamp current envelopes (e.g., 502, 602, 702, 802, and 902) and modulated in accordance with embodiments of the present system. Accordingly, the process may set a desired lamp current as shown in FIGS. 5-9 (eg, 500, 600, 700, 800 and 900). FIGS. 5-9 show exemplary lamp current envelopes (eg, 502, 602, 702, 802, and 902) based on experiments, obtained using an SCM according to an embodiment of the present system. Tables 1 to 5 show the corresponding SCM schemes for obtaining the desired lamp current, which are exemplarily shown in FIGS. 5 to 9, respectively. Thus, for example, if the lamp current envelope shown in FIG. 5 is required, the process may select the SCM scheme shown in Table 1 below. Similarly, for example, if the lamp current envelope shown in FIG. 6 is required, the process may select the SCM scheme shown in Table 2 below. The SCM scheme may be specific to the ballast and / or lamp type and may be based on experimental results or the like. If necessary, the process may select a default SCM scheme.

  With respect to Table 1, multiple segments (eg, 16 50 μsec time segments (i)) are shown, during which the modulated signals Ton1 and Ton2 are described as described for the corresponding segment (i). , Calculated by processing. According to an embodiment of the system, Ton1 is generated (eg, by DCR 108) and a first gate drive signal (eg, Gate_drive_1) that is transmitted to the high gate (eg, Q1) of the half bridge is turned on. Say time. Ton2 refers to the time during which a second gate drive signal (eg, Gate_drive_2) generated (eg, by DCR 108) and transmitted to the low gate (eg, Q2) of the half bridge is on. Modulated Ton1 and Ton2 may be referred to as Ton1 'and Ton2', respectively. According to an embodiment of the present system, Ton for a given segment is based on feedback obtained from the previous period to control the half-bridge output current of the current period, eg, according to a 50% duty cycle, Generated.

  With respect to the number of segments in Tables 1-5 and / or duration, the segments in these tables are repeated (eg, in numerical order starting from the first segment) to span the corresponding period time interval. Also good. Thus, with respect to Table 5, the first and second segments may be repeated in order, the number of times until the period is complete. Also, if the period is completed between the first segment and the last segment, the corresponding table of Tables 1 to 5 or the corresponding table of the user setting or system setting table as applicable The process may complete the current cycle without completing the last segment shown.

Tables 2 through 5 are similar to Table 1 and will not be described in detail to simplify the discussion herein. According to embodiments of the present system, other segments of Ton1 and Ton2 are applicable as appropriate, but Tables 1 through 5 show different SCMs applicable to generate the lamp current envelope as shown. The system is illustrated.

  For various SCM schemes as shown in Table 2, some segments are symmetric (eg, they are symmetric or asymmetric as opposed to being asymmetric, such as segments 15 and 16). And may be mixed with multiple asymmetric segments if necessary. FIG. 3 illustrates a pulse width modulated output from a controller (eg, control unit 102) to a half-bridge driver to generate the current envelope shown in FIG. 9, in accordance with an experimental embodiment of the system. This is a screen shot of the graph 300. First and second segments (eg, segment) of the PWM gate drive signal 307 (see also C2 and Z2) according to the SCM scheme shown in Table 5 and the resulting output shown in FIG. A lamp current envelope 305 (C1) and a waveform 306 (Z1) are shown (Z1 is the lamp) simultaneously with the graph showing the transition for the half-bridge switch between (1) and segment (2)). It is a minute portion of the enlarged portion of the current envelope C1). For the lamp current 306, for example, a sinusoidal waveform as shown may be formed.

  After completing act 211, processing may continue to act 213.

  In operation 213, the process may determine Ton1 'and Ton2' for each corresponding segment based on the selected SCM scheme. Thus, for example, the process may obtain Ton and calculate Ton1 'and Ton2' for each segment. As described above, Ton1 'and Ton2' are modulated according to the selected SCM method.

With respect to Tables 1-5, the asymmetrical modulation of the inputs (eg, mos field effect transistors (MOSFETs) Q1 and Q2) to the duty cycle of the half-bridge circuit can effectively control the discharge fringes of the lamp. Specifically, in the exemplary embodiments shown in Tables 1-5, generally Ton1 ′ and Ton2 ′ may be set according to Equation 1 for multiple segments (i) within the duration of one cycle. :
Ton1 ′ (i) = Ton + kx (i), and
Ton2 ′ (i) = Ton−kx (i). . . . . Formula (1)
Where Ton is set to control the current delivered to the load according to a 50% duty cycle, k is a constant, and x (i) varies according to each segment (i). x (i) may be bounded to be greater than the first integer and less than the second integer, or may be an integer having a value less than or equal to a threshold (eg, 40) For example, it may be generated by a random number generator. For k, this value may be an integer and may be used for multiplication with the corresponding value of x (i) if necessary. It is envisioned that a random number generator may be included to generate k in real time. However, the multiple values for k generated by the random number generator may be limited to be within the range for stable operation of embodiments of the present system. In other words, the plurality of values for k may be limited to a plurality of values that can maintain the function of the output stage of the ballast.

  Also, for x (i), this value can be, for example, a pulse width modulation (PWM) that is modulated to form first and second gate drive signals formed by DCR 108 (eg, Gate_drive_1 and Gate_drive_2, respectively). ) Waveform resolution (eg, minimum step time). Thus, the resolution may depend on the hardware used to form the PWM waveform. According to several embodiments of the system, the resolution may be illustratively set to 16 ns, but other multiple values are also envisioned.

  Also, in embodiments of the system, the number of segments and the duration of each segment may be correlated and interdependent. For example, in the embodiments shown in Tables 1 through 2 and 4, 16 segments having a duration of 50 μs are used. However, other numbers of segments and / or durations of each segment are also envisioned. According to embodiments of the system, the number of segments and / or segment duration may be set / changed as a function of ballast output (eg, dimming).

  After completion of operation 213, processing may continue to operation 215. During operation 215, processing is determined as described above for each current cycle (in the current example, eg, starting from the current operation and lasting the duration of the cycle, eg, 850 μsec) (each High gate Q1 and low gate Q2 may be driven according to Ton1 ′ and Ton2 ′, respectively, for segment (i) or until the corresponding period ends. Thus, the process may generate a first drive signal (eg, Gate_drive_1) during each segment of the period according to Ton1 ′ and send this signal to the high gate (Q1); and according to Ton2 ′ A second drive signal (eg, Gate_drive_2) may be generated and transmitted to the low gate (Q2) of the half bridge. As described above, if it is determined that all segments (i) are or will be completed before the end of the current cycle occurs, processing is performed (eg, from the start of the first segment). The plurality of segments (i) may be repeated, and corresponding first and second drive signals may be generated according to the repeated segments until the current cycle ends. Thus, during operation 215, the process may modulate high switch Q1 and low switch Q2 according to the selected SCM scheme to reduce or eliminate the discharge fringes of the lamps driven by the half bridge. Accordingly, referring back to FIGS. 4-9, the duty cycle modulation may be changed every 50 μS (eg, for each segment to be changed) for one period.

During operation 217, the process may obtain feedback information (eg, IHB_av). The feedback information may be used to control the half-bridge load current (eg, I _LOAD ) during the next period. According to embodiments of the system, the feedback signal may be acquired once or multiple times in a cycle and the average calculated. After completion of operation 217, processing may continue to operation 219.

During operation 219, the process may determine Ton for the next period according to the feedback information obtained during operation 217. Thus, the process may analyze feedback information obtained during operation 217, such as IHB_av, and control (eg, regulate) the half-bridge output current (I _LOAD ) during the next cycle. Therefore, Ton may be adjusted according to a 50% duty cycle (eg, for a half bridge). After completion of operation 219, processing may continue to operation 221.

  During operation 221, the process may determine whether the current cycle has ended. Accordingly, if it is determined that the current cycle has ended, the process may repeat operation 209. However, if it is determined that the current cycle has not ended, the process may continue to apply multiple segments during operation 215 and then repeat operation 211 until it is determined that the cycle has ended. Good. As can be readily understood by those skilled in the art, it is not necessary to apply operations 217 and 219 after each segment, as illustrated in the presented flowchart shown to simplify the discussion herein. There may be no and, according to embodiments of the system, during each period, operations 217 and 219 may be applied only once or more times.

  As described above, during operation 209, if it is determined not to enable SCM, processing may continue to operation 223. During operation 223, processing may set Ton1 and Ton2 equal to Ton for the current period and may continue to operation 225. Therefore, Ton1 and Ton2 are not modulated during the corresponding period.

  During operation 225, the process may start the current period and drive the half bridge for the current period according to Ton1 and Ton2. Thus, the process may drive the high gate (Q1) and the low gate (Q2), respectively, according to Ton1 and Ton2 for the current period (eg, 850 μsec) and during this time (for the current period) Neither Ton, Ton1, nor Ton2 is changed. Thus, the process may generate a first drive signal (eg, Gate_drive_1) according to Ton1 for the current period and send this signal to the high gate; and according to Ton2, the second drive signal (E.g., Gate_drive_2) may be generated and this signal sent to the low gate (Q2) of the half bridge. Unlike operation 215, during operation 225, the first and second gate drive signals are formed according to Ton and do not substantially change in the current period. After initiating operation 225, processing may continue to operation 217 and then continue as described above. Referring back to FIG. 4, this figure illustrates the baseline (lamp) current envelope 402 and the duration ST and amplitude due to the filament heating circuit being turned on and off. A notch (ST) with STA is shown. Note that the current envelope appears to have a (sinusoidal) standing wave pattern that is illustrated by line 403 and may be punctured by a notch (ST). The standing wave pattern also appears in the portion below the current envelope. The discharge fringe control (eg, discharge fringe prevention) method of the present system can change the envelope of the lamp current in order to reduce or completely prevent the discharge fringes in the lamp (FIGS. 5-9, And see FIG. Thus, according to embodiments of the present system, the modulation of the drive signal corresponding to each gate of the half bridge circuit modulates the envelope of the output current of the lamp driven by the half bridge circuit, thereby resulting in Reduce or substantially eliminate the discharge fringes of the generated lamp. According to several embodiments of the system, this operation can be regarded as a frequency dimming method for discharge fringe control. Also, with respect to the plurality of cuts ST shown in FIGS. 4 to 9, these cuts may be removed, for example, by disabling the filament heating circuit (eg, turning it off).

  FIG. 10 illustrates a portion of a system 1000 (eg, including the control unit 102, etc.) according to embodiments of the system. For example, a portion of the system may include a processor 1010, one or more sensors 1060, a half bridge 1050, and a user input 1070 operably coupled to the memory 1020. Sensor 1060 includes any suitable sensor, such as a voltage, current, temperature, and / or image sensor (eg, analog digital (AD) type, etc.) that can provide sensor information that can be analyzed by the system. But you can. Memory 1020 may be any type of device (ie, temporary and / or non-transitory) for storing application data and other data related to the operations described. Application data and other data are received by processor 1010 to configure (eg, programming) so that processor 1010 can perform operation acts in accordance with the present system. The processor 1010 configured as described above is a dedicated machine that is particularly suitable for execution according to the present system. The processor 1010 may be coupled to the half bridge 1050 and generate a plurality of signals for driving the half bridge 1050 to power a load 1040 that may include one or more lamps and resonant circuits. May be.

  The operational action may include controlling the operation of a load such as one or more lamps. User input 1070 may include a light switch, keyboard, mouse, trackball or other device for controlling the operation of the lamp. User input 1070 can be used for information exchange with processor 1010, including enabling interactions within the UI as described herein, such as selecting an SCM method. Also good. Obviously, in these embodiments, the processor 1010 selects a method suitable for cold fringe fringe control in response to one or more sensors detecting appropriate operating conditions, etc. It may operate to control the SCM scheme without any intervention. Clearly, the processor 1010, memory 1020, and / or user input device 1070 may be all or part of a computer system or other device, as described herein.

  The method of the system is particularly suitable for being executed by a computer software program, such as a program comprising modules that correspond to one or more individual steps or operations described and / or envisaged by the system. ing. Such a program may, of course, be embodied in computer readable media such as an integrated chip, a peripheral device, or a memory such as memory 1020 or other memory coupled to processor 1010.

  A program and / or program portions included in memory 1020 configure processor 1010 to perform the methods, operational acts, and functions disclosed herein. To do. The plurality of memories may be distributed or local, and if additional processors may be provided, the processor 1010 may also be distributed or local. The plurality of memories may be implemented as electrical, magnetic or optical memory, or any combination thereof or other type of storage device. Further, the term “memory” should be interpreted broadly enough to encompass any information that is readable or writable from an addressable space address available by the processor 1010. It is. According to this definition, the information that can be used via the network is, for example, in the memory because the processor 1010 can acquire the information from the network for the operation according to the present system.

  The processor 1010 is operable to provide a plurality of control signals and / or to perform a plurality of operations in response to a plurality of input signals from the user input 1070, the plurality of sensors 1060. Similarly, processor 1010 is operable in response to a plurality of other devices in the network and for executing instructions stored in memory 1020. The processor 1010 may be application specific integrated circuit (s) or general application integrated circuit (s). The processor 1010 may be a dedicated processor for executing in accordance with the present system, or a general-purpose processor in which only one of a plurality of functions operates to be performed in accordance with the present system. Also good. The processor 1010 may operate using a part of a program, a plurality of program segments, and / or may be a hardware device using a dedicated or general-purpose integrated circuit.

  It is envisioned that embodiments of the present system may be embedded in one or more chips, such as an integrated circuit (IC) chip, for example, to form a ballast control IC. It is also envisioned that embodiments of the system may be compatible with analog controlled ballasts. For example, a modulation circuit is added to change the half-bridge duty cycle in the same way as the digital version to control the discharge fringes at the output of one or more lamps driven by an analog controlled ballast. Also good.

  The system can also work with dimmable and / or non-dimmable fluorescent ballasts. Embodiments of the system may be interfaced with standard fluorescent lights and energy saving fluorescent lamps and / or lighting fixtures including these lamps.

  Thus, by slightly changing the duty cycle of the half bridge 104 (eg, by changing the duty cycle of the first and second gates), the discharge fringes are minimized or reduced in the plurality of lamps 106. Can be removed. Accordingly, the DCR 108 can operate during one or more operating modes such as steady mode, normal mode, dimming mode, failure mode, and various operating conditions (eg, multiple temperature ranges, low temperature, high temperature, full temperature range). , It is possible to control a plurality of discharge fringes in one or more lamps. Each of them may have one or more corresponding discharge fringe prevention methods, patterns, and / or settings assigned to it. According to multiple embodiments of the system, the DCR 108 can control the discharge fringes in multiple lamps that are controlled using the same or different SCM methods.

  Finally, the above discussion is merely intended to illustrate the present system and should not be construed as limiting the appended claims to a particular embodiment or group of embodiments. . Although the system has been described with reference to a number of exemplary embodiments, numerous modifications can be made without departing from the broader and intended spirit and scope of the system as set forth in the claims below. It should be understood that variations and alternative embodiments can be devised by those skilled in the art. The specification and drawings are, accordingly, to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

In interpreting the appended claims, the following should be construed:
a) the word “comprising” does not exclude the presence of other elements or acts than those listed in a given claim;
b) the word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements;
c) any reference signs in the claims do not limit their scope;
d) several “means” may represent the same item or structure or function implemented in hardware or software;
e) any of the disclosed elements may be comprised of a plurality of hardware portions (eg, discrete and integrated electronic circuits), a plurality of software portions (eg, computer programs), and any combination thereof. May be;
f) The plurality of hardware portions may include one or both of analog and digital portions;
g) unless otherwise noted, any of the disclosed devices or portions thereof may be combined or separated into more portions;
h) unless otherwise indicated, it is not intended that a specific order of actions or steps be required;
i) The term “plurality of” element includes two or more elements of a claim and does not imply a particular range of the number of elements; It may be two elements and may include an innumerable number of elements.

Claims (20)

An apparatus for supplying power to one or more gas lamps,
The apparatus includes a half bridge driver having a discharge fringe control circuit,
For each of the plurality of segments, the discharge fringe control circuit controls the on-time Ton1 and Ton2 of the first and second power switches of the half bridge circuit according to the discharge fringe control method, respectively. A device characterized by being a circuit.   The apparatus according to claim 1, wherein the discharge fringe control circuit modulates Ton1 and Ton2 to be different from each other in a predetermined segment of each of the plurality of segments in the period.   The apparatus according to claim 1, wherein the discharge fringe control circuit modulates Ton1 and Ton2 according to a predetermined discharge fringe control pattern of the discharge fringe control method. The discharge fringe control circuit sets Ton1 and Ton2 according to the following formula for a plurality of segments (i) in the cycle:
Ton1 (i) = Ton + kx (i), and
Ton2 (i) = Ton−kx (i),
Ton is set to regulate the current supplied to the load according to the 50% duty cycle, k is a constant, and x (i) varies with each segment (i). Device according to claim 3, characterized in that   The discharge fringe control circuit determines whether or not the last segment (i) of the plurality of segments is completed, and among the plurality of segments starting from the first segment of the plurality of segments The apparatus of claim 1, wherein one or more of the above are repeated until it is determined that the period is complete. The discharge fringe control circuit is:
Determining whether discharge fringes are present in the output of the one or more gas lamps;
If it is determined that discharge fringes are present in the output of the one or more gas lamps, each of the first and second power switches of the half-bridge circuit according to the discharge fringe control method for each of the plurality of segments. , Ton1 and Ton2; and if it is determined that no discharge fringes are present in the output of the one or more gas lamps, set Ton1 and Ton2 equal to each other and set equal to Ton. Device according to claim 1, characterized.   The discharge fringe control circuit determines the presence of discharge fringes in the output of the one or more gas lamps based on one or more of dimming settings and temperatures of the one or more lamps. The apparatus according to claim 6. A method for controlling a switching half-bridge circuit for supplying power to a load, the method comprising one or more operations performed by a processor, the operations comprising:
Determining a turn-on time (Ton) for a period comprising a plurality of segments and lasting a predetermined time interval according to a 50 percent duty cycle; and for each of the plurality of segments according to a discharge fringe control method; Modulating the Ton1 and Ton2, which are the times of turn-on of the first and second power switches, respectively, of the half-bridge circuit.   9. The method of claim 8, further comprising: modulating Ton1 and Ton2 to be different from each other in a predetermined segment, and modulating Ton1 and Ton2 to be different from Ton for a plurality of segments in the period. The method described.   9. The method of claim 8, further comprising an operation of modulating Ton1 and Ton2 according to a predetermined discharge fringe control pattern. The operation further includes setting Ton1 and Ton2 according to the following equation for a plurality of segments (i) in the period:
Ton1 (i) = Ton + kx (i), and
Ton2 (i) = Ton−kx (i),
Ton is set to regulate the current supplied to the load according to a 50% duty cycle, k is a constant, and x (i) varies with each segment (i). The method according to claim 10. Determining whether a last segment (i) of the plurality of segments is complete; and one or more of the plurality of segments from the first segment of the plurality of segments; Repeats until it is determined that the cycle is complete;
The method of claim 8, further comprising: An operation for determining whether or not to operate in the discharge fringe control mode (SCM); and an operation for setting Ton1 and Ton2 according to the discharge fringe control setting when it is determined to operate in the SCM;
The method of claim 8, further comprising: An operation of determining whether or not discharge fringes are present in the output of the load;
If it is determined that a discharge fringe is present in the output of the load, Ton1 for each of the first and second power switches of the half-bridge circuit according to the discharge fringe control method for each of the plurality of segments An operation for modulating Ton2; and an operation for setting Ton1 and Ton2 equal to each other and equal to Ton when it is determined that no discharge fringes are present in the output of the load;
The method of claim 8, further comprising:   Determining whether discharge fringes are present in the output of the one or more gas lamps based on one or more of dimming settings and temperatures of the one or more gas lamps. Item 9. The method according to Item 8. A computer program for supplying power to one or more gas lamps stored in a computer-readable non-transitory storage medium,
Determining an on time (Ton) for a period having a plurality of segments and lasting a predetermined time interval according to a 50 percent duty cycle;
For each of the plurality of segments, according to a discharge fringe control method, modulate Ton1 and Ton2, which are on-times of the first and second power switches of the half bridge circuit, respectively; and according to Ton1 and Ton2, respectively Generating first and second control signals for driving the first and second power switches, respectively;
A computer program comprising a program part.   The program portion further modulates Ton1 and Ton2 to be different from each other in a predetermined segment, and modulates Ton1 and Ton2 to be different from Ton for a plurality of segments in the period. The computer program according to claim 16.   The computer program according to claim 16, wherein the program part further modulates Ton1 and Ton2 according to a predetermined discharge fringe control pattern. The program portion further sets Ton1 and Ton2 according to the following formula for a plurality of segments (i) in the cycle:
Ton1 (i) = Ton + kx (i), and
Ton2 (i) = Ton−kx (i),
Ton is set to regulate the current supplied to the load according to the 50% duty cycle, k is a constant, and x (i) varies with each segment (i). The method of claim 16, wherein the method is characterized. A ballast for supplying power to fluorescent lamps:
A half bridge circuit having first and second switches in series with each other and an output for supplying power to the fluorescent lamp;
A power supply circuit for regulating the supply of direct current (DC) voltage to the input of the half-bridge circuit; and an on time (Ton) corresponding to a 50% duty cycle for a period having a plurality of segments; A modulation value M (i) for each of the segments (i) is determined, and for each of the plurality of segments of the period, Ton1 = Ton + M (i) and Ton2 = Ton−M (i) Generating a first signal for driving the first switch at a first on time (Ton1) and a second signal for driving the second switch at a second on time (Ton2); Regulator to do;
A ballast characterized by comprising:

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